If N is a positive number, extend given string S, for N places, using character C. Complete it using a function and in the main function check if the function works. Any value of N gives me "it doesn't work".
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int cat(char*,char,int);
int main()
{
char S[20],C;
int N;
puts("Enter N: ");
scanf("%d",&N);
puts("Enter string: ");
gets(S);
if (N<1)
printf("it's unknown whether it works");
else if(cat(S,C,N)==strlen(S)+N)
printf("it works.");
else
printf("it doesn't work.");
}
int cat(char*S,char C,int N){
int i;
char T[20];
for(i=0;i<N;i++)
T[i]=C;
return strlen(strcat(S,T));
}
You need to initialize the C character variable:
char C = 'C';
The strcat function concatenates the 2 string parameters & returns a string whose length is equal to the sum of the 2 strings' length. So you need to declare a new array whose size is string1 + string2's length in the cat function that will hold the concatenation result. Then return its length.
Related
#include <stdio.h>
#include <string.h>
int countLetters(char *string1, char letter){
int count=0;
for(int i=0; i<strlen(string1); i++){
if(string1[i]=letter){
count++;
}
}
return count;
}
int main(){
char string1[200];
char letter;
int count;
printf("\nEnter the string: \n");
fgets(string1, 200, stdin);
printf("\nEnter character to be searched: \n");
scanf("%c", &letter);
count = countLetters(string1, letter);
printf("\nThe number of occurrences: %d", count);
}
I was expecting for the function to output the number of times each letter of the array was equal to the char(letter) inputted by the user, but it is just giving me the length of the string.
Change the line:
if(string1[i]=letter){
to
if(string1[i]==letter){
Note, that the string1[i]=letter was overwriting data in string1[i].
You have to use equal equal to operator instead of assignment operator in if condition like this
if(string1==latter)
in your if condition if(string1=latter) value of latter variable is assign to string1[i]
I wrote this code to input names to array (eg:Jon,raj...) and the input part is ok but how to print exact name that i input to this array a[5] why this code is not working
#include <stdlib.h>
#include<stdio.h>
int main(){
int i;
char a[5];
for(i=0;i<5;i++){
printf("Enter ");
scanf("%s",&a[i]);
}
for(i=0;i<5;i++){
printf("%s \n",a[i]);
}
}
Your array a is an array of chars. This means that in each position you will have only one char.
You can do this any one of these two ways:
Pre-allocated (array of arrays of chars)
#include <stdio.h>
int main(){
const int NAME_MAXIMUM_SIZE = 50;
const int NUMBER_OF_NAMES = 5;
int index;
char names [NUMBER_OF_NAMES][NAME_MAXIMUM_SIZE];
for(index=0; index<NUMBER_OF_NAMES; index++){
printf("Enter ");
scanf("%49s",names[index]);
}
for(index=0; index<NUMBER_OF_NAMES; index++){
printf("%s \n",names[index]);
}
}
Malloc + free (array of pointers)
#include <stdio.h>
#include <stdlib.h>
int main(){
const int NAME_MAXIMUM_SIZE = 50;
const int NUMBER_OF_NAMES = 5;
int index;
char *names [NUMBER_OF_NAMES];
for(index=0; index<NUMBER_OF_NAMES; index++){
names[index] = (char*)malloc(NAME_MAXIMUM_SIZE);
printf("Enter ");
scanf("%49s",names[index]);
}
for(index=0; index<NUMBER_OF_NAMES; index++){
printf("%s \n",names[index]);
free(names[index]);
}
}
You can make use of 2 dimensional array. Here your variable a which is a character array stores only one character at each index.
#include <stdlib.h>
#include<stdio.h>
int main(){
int i;
char a[5];
for(i=0;i<5;i++){
printf("Enter ");
scanf("%s",&a[i]);
}
for(i=0;i<5;i++){
printf("%s \n",a[i]);
}
}
"...wrote this code to input names to array..."
char a[5] does not create 5 C strings. It is simply an array of 5 char. It provides room for only 1, 4 character C string (leaving room for the \0 terminator). If you need an array of names, of typical size the code will need an array of arrays each with space sufficient for typical names. For example:
char a[5][80] = {{0}}; //provides an array capable of containing 5 names
Also, in the read statement: scanf("%s",&a[i]);, the format code %s is expecting to process an array of char. But is provided with &a[i] which is only a single character. If you are going to use scanf, then call it like this: scanf("%s",a); Same issue with the print statement.
Make the following edits to address these basic issues:
int main(void)
{
int i = 0;
char a[5][80] = {{0}};//space for 5 names, each with up to 79 characters
//arrays are initialized to zeros
for(i=0;i<sizeof(a)/sizeof(a[0]);i++)//sizeof(a)/sizeof(a[0]) is flexible way to
//loop only through number of names.
//If array size changes, expression will still work
{
printf("Enter name %d:\n ", i+1);
scanf("%79s",a[i]);//limit input to prevent overflow
// ^^
}
for(i=0;i<sizeof(a[0])/sizeof(a[0][0]);i++)
{
printf("%s \n",a[i]);
}
return 0;
}
I'm supposed to write a simple C program to read in an integer and loop n times to work on the string, but the first loop automatically passes an empty string if I use the scanf integer, but if I use a constant number the loop works right. Somebody please explain to me what's going on.
#include <stdio.h>
#define MAX 80
int main(){
char sentence[MAX];
int n, i;
scanf("%d", &n);
for(i=0; i<3; i++){//it loops with empty string automatically if I replace 3 with n
gets(sentence);
printf("%s\n", sentence);
}
}
Try this code
#include<stdio.h>
#include<conio.h>
#define MAX 80
void main()
{
char sentence[MAX];
int n,i;
clrscr();
scanf("%d",&n);
for(i=0;i<n;i++)
scanf(" %99[^\n]",sentence);
printf("\n%s\n",sentence);
getch();
}
So i have this type of problem. How to make an array 1*x and then sum up its digits together. I wrote down something like this for now. Any ideas? Thank you.
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
/* run this program using the console pauser or add your own getch, system("pause") or input loop */
int main(int argc, char *argv[])
{
int a,i,w,j,m;
int s[a];
printf("How many digits do you want to sum up\n");
scanf("%d",&a);
for(i=0;i<a;i++)
{
printf("Enter numer %d: ",i);
scanf("%d",&s[i]);
}
for(j=0;j<a;j++)
{
m=s[j]+s[j++];
}
printf("\n %d",m);
return 0;
}
The problems of your code are:
int a;
int s[a];
Here a is uninitialized.So,array size is unknown which is incorrect.And,instead of this
m=s[j]+s[j++];
you should do like this :
m += s[j];
One more thing,you have initialize m = 0 before starting to add.
I've Changed your program to this:
#include <stdio.h>
int main(int argc, char *argv[]) {
int a,i,m = 0;
//First get the array size
printf("How many digits do you want to sum up\n");
scanf("%d",&a);
//Then declare the array with the size (a)
int s[a];
for(i = 0; i < a; i++){
printf("Enter numer %d: ",i);
scanf("%d",&s[i]);
m += s[i];
}
printf("\n %d",m);
return 0;
}
Using uninitialized variable is undefined behaviour.
int s[a];
The above statement defines an array s of size a but the value of a is unpredictable since it is uninitialized and contains garbage. The size of the array must be known when it defined and it remains the same throughout its lifetime. You cannot resize your array by changing the value of a here. You can use dynamic memory allocation using malloc.
Further, the following statement again invokes undefined behaviour -
m=s[j]+s[j++];
That's because it violates the the following rule stated in the C99 standard §6.5 ¶2
Between the previous and next sequence point an object shall have its
stored value modified at most once by the evaluation of an expression.
Furthermore, the prior value shall be read only to determine the value
to be stored.
I am new to c programming. I have created a program for entered letters and finally displayed the entered letters.. but it displayed only final letters always.. please help .. i know its simple question but am beginner so please help guys..
#include<stdio.h>
int main()
{
char z;
int a;
printf("enter the no.");
scanf("%d",&a);
printf("the entered no. is:%d\n",a);
int i;
for(i=0;i<a;i++)
{
printf("enter the letters:");
scanf("%s",&z);
}
printf("the entered letters are:");
for(i=0;i<a;i++)
{
printf("%s\n",&z);
}
return 0;
}
Problems:
You should use %c (for character) instead of %s (for string).
Use a character array for storing multiple characters. Read about arrays here.
Remove & from printf() in the second for loop.
Try this:
int main()
{
char z[10]; //can hold 10 characters like z[0],z[1],z[2],..
int a;
printf("enter the no.");
scanf("%d",&a);
printf("the entered no. is:%d\n",a);
int i;
for(i=0;i<a;i++)
{
printf("enter the letters:");
scanf("%c",&z[i]);
}
printf("the entered letters are:");
for(i=0;i<a;i++)
{
printf("%c\n",z[i]);
}
return 0;
}
Please look into this for more details on scanf. You have given scanf("%s",&z); %s is for reading strings(array of chars except newline char and ended with null char). So if you put this inside loop you wont get desired result. And if you want read only a char at a time use %c here c for Character.
for(i=0;i<a;i++)
{
printf("enter the letters:");
scanf("%c",z+i);
}
char z is a place holder for one character only. And you are over writing what you set z to in the for loop. To take in more characters, use a char array as others have mentioned.
Or print the characters in the same you loop you are scanning them:
#include<stdio.h>
int main()
{
char z;
int a;
printf("enter the no.");
scanf("%d",&a);
printf("the entered no. is:%d\n",a);
int i;
for(i=0;i<a;i++)
{
printf("enter the letters:");
scanf("%s",&z);
printf("letter scanned:%c\n", z);
}
return 0;
}
Letters are scanned using %c. And to scan multiple letters you can use char array: char z[10];
What you are trying to do can be done this way:
char z[10]; // Take some max size array
...
for(i=0;i<a;i++)
{
printf("enter the letters:");
scanf("%c",&z[i]); // Scan the letters on each array position.
}
printf("the entered letters are:");
for(i=0;i<a;i++)
{
printf("%c\n",z[i]); //'printf' doesn't require address of arg as argument hence no `&` required
}
%s argument is used to scan a string of chars.
Note the difference between string of chars and array of chars. The string of chars in C needs to be terminated with ASCII Character 0 represented as \0 in char format, while the array of char is just a collection of letters which need not be terminated with \0.
The difference becomes more important when you try to perform some operation on strings such as printf, strcpy, strlen, etc.. These functions work on null character termination property of string.
For Example: strlen counts the characters in the string till it finds \0, to find out the length of string. Similarly, printf prints the string character by character until it finds the \0 character.
UPDATE:
Forgot to mention that scanf is not a good option to input char format. Use fgetc instead, with stdin as input FILE stream.
#include <stdio.h>
int main()
{
char *z;
int a;
printf("enter the no.");
scanf("%d",&a);
z = (char *) malloc(a);
printf("the entered no. is:%d\n",a);
int i;
for(i=0;i<a;i++)
{
printf("enter the letters:");
scanf("%c",z+i);
}
printf("the entered letters are:");
for(i=0;i<a;i++)
{
printf("%c\n",z);
}
return 0;
}
first error in your code is you have used "%s" instead of "%c".Second is it is impossible to store multiple values in one variable so instead of using variable use arrays.third is that you have told the user to enter the number of character that he/she wants to entered which you don't know.They can enter 1 also and 100000 also so the number of members in array is not defined.Better is to use specific number of characters in array.
finally i got the answer thank you for the help stackoverflow guys simply rocks ...
#include<stdio.h>
#include<malloc.h>
int main()
{
int a;
char *z=(char *)malloc(sizeof(a));
printf("enter the no.");
scanf("%d",&a);
printf("the entered no. is:%d\n",a);
int i;
for(i=0;i<a;i++)
{
printf("enter the letters:");
scanf("%s",&z[i]);
}
printf("the entered letters are:\n");
for(i=0;i<a;i++)
{
printf("%c\n",z[i]);
}
return 0;
}