strcmp refuses to work [closed] - c

Question

Closed. This question needs debugging details. It is not currently accepting answers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 5 years ago.
Improve this question
I've tried everything, yet strcmp (as well as strncmp) always give a value other than 0, both with and without using pointers, as well as inside and outside functions. What should I do?
The point of the program is to create a student data system for signing up and in, as well as managing and sorting said data, the latter which I haven't implemented yet.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int signup(char* ET, char* OT, int* G1T, int* G2T, int* G3T, int* avg, char* status, int* LI, int* sT, int* TT, char** UT, int** PT)
{
int i;
char LU[21];
int ID;
if (strcmp (status, "Register") == 0)
{
printf("Enter last name: ");
scanf("%s", ET);
printf("Enter first name: ");
scanf("%s", OT);
while(1)
{
printf("Enter C grade: ");
scanf("%d", G1T);
if (*G1T >= 0 && *G1T <= 10)
{
break;
}
}
while(1)
{
printf("Enter Java grade: ");
scanf("%d", G2T);
if (*G2T >= 0 && *G2T <= 10)
{
break;
}
}
while(1)
{
printf("Enter C++ grade :");
scanf("%d", G3T);
if (*G3T >= 0 && *G3T <= 10)
{
break;
}
}
*avg = (*G1T + *G2T + *G3T)/3;
*UT[*TT] = *ET;
*sT = 1;
}
else
{
printf("Enter username: ");
scanf("%s", &LU);
for (ID = 0; ID < 100; ID++)
{
if (strncmp(LU, UT[ID], 20) == 0)
{
break;
}
}
if (ID == 100)
{
return 0;
}
else
{
printf("Enter password: ");
scanf("%s", LU);
}
}
return 0;
}
void pass(char** User, int** Pass, int* Total)
{
int cd[21];
int i, j;
for (i=0; i<21; i++)
{
cd[i] = *User[i];
if (i%2 == 0)
{
if(cd[i] >= 97 && cd[i <= 122])
{
cd[i] = cd[i] - 32;
}
}
else
{
if(cd[i] >= 65 && cd[i] <= 90)
{
cd[i] = cd[i] + 32;
}
}
}
}
int main(void) {
int i, j, z;
int succ, *sT;
char intro[9], *status;
int Total = 0;
int* TT;
int LoggedIn = 0;
int* LI;
char Ep[100][21], *ET, On[100][21], *OT;
int Age[100], *AgeT, Gr1[100], *G1T, Gr2[100], *G2T, Gr3[100], *G3T, avg[100], *avgT;
char UN[100][21], *UT[100];
int PW[100][21], *PT[100];
while(1)
{
system("cls");
if (succ = 0)
{
printf("ERROR: Last name found.");
}
succ = 1;
while(1)
{
printf("Type your option (Login/Register): ");
scanf("%s", intro);
if ((strcmp (intro, "Login") == 0) || (strcmp (intro, "Register") == 0))
{
break;
}
}
if ((strcmp (intro, "Login") == 0) || (strcmp (intro, "Register") == 0))
{
for(i = 0; i < 100; i++)
{
UT[i] = &UN[i][0];
PT[i] = &PW[i][0];
}
ET = &Ep[Total][0];
OT = &On[Total][0];
G1T = &Gr1[Total];
G2T = &Gr2[Total];
G3T = &Gr3[Total];
avgT = &avg[Total];
LI = &LoggedIn;
status = &intro[0];
sT = &succ;
TT = &Total;
signup(ET, OT, Gr1, Gr2, Gr3, avg, status, LI, sT, TT, UT, PT);
for(i = 0; i<Total; i++)
{
if(strncmp(UN[Total], UN[i], 20) == 0)
{
succ = 0;
}
}
if (succ == 1)
{
pass(UT, PT, TT);
Total++;
}
}
}
return 0;
}
An example for my inputs is the following:
Register
LastName
FirstName
4
5
6
Then:
Register
LastName
FN2
7
6
5
And I expect to see "ERROR: Last name found." right above the starting message. However, it never appears, suggesting strcmp failed.

Answer 1

First off, you're allocating a lot of arrays in local variables in main(). That could lead to a stack overflow. You should probably use malloc() to allocate them instead.
Second, this line is an assignment, not a comparison, which is a bug:
if (succ = 0)
Change it to this, if you want it to be a comparison:
if (succ == 0)
Third, you're not initializing succ at the beginning of main() which is a bug.
If I see anything else suspect I'll update my answer. But start with fixing those issues.

Answer 2

There are a few issues with your code, as was pointed out, but the reason it doesn't work as you expect is the line: if(succ = 0)
I changed it to: if(succ==0)
And it worked as you described.
Additionally this line here: scanf("%s", &LU); should be scanf("%s", LU);
The compiler is probably generating a warning about the format.