How can I pass a matrix to a double pointer function? - c

Question

I have a problem with this program, the program must simply output the minimum value contained in a matrix, this must be done by the function that has as parameter the double pointer (**A) that would be the array , the problem is that after inserting the items , the program finishes and returns nothing.
(I don’t even appear written outuput instruction )
#include<stdio.h>
#include<stdlib.h>
int minium_matrix_value(int **A, int rows, int columns) {
int min=A[0][0];
for(int i=0;i<rows;i++){
for(int j=0;j<columns;j++)
if(A[i][j]<min)
min=A[i][j];
}
return min;
}
int main(){
int** A;
int i, j;
int result;
int sizer=100, sizec=100;
A = (int**)calloc(sizer,sizeof(int*));
A = (int**)calloc(sizec,sizeof(int*));
printf("insert rows size");
scanf("%d",&sizer);
printf("insert columns size");
scanf("%d",&sizec);
printf("insert matrix elements");
for( i=0; i < sizer; i++ )
for( j=0; j < sizec; j++ ) {
scanf("%d",((A+i)+j));
}
result=minium_matrix_value(A,sizer,sizec);
printf("the minium elements is: %d",result);
return 0;
}

Answer 1

You only allocated arrays to store pointers to rows. You have to allocate arrays for storing values of each rows.
Using the value of sizer should be after reading value into that/
// move this after scanf()
// A = (int**)calloc(sizer,sizeof(int*));
// remove this, or memory leak occur
// A = (int**)calloc(sizec,sizeof(int*));
printf("insert rows size");
scanf("%d",&sizer);
printf("insert columns size");
scanf("%d",&sizec);
// move here
A = calloc(sizer,sizeof(int*));
printf("insert matrix elements");
for( i=0; i < sizer; i++ ) { // add { to do multiple things
A[i] = calloc(sizec,sizeof(int)); // allocate row array
for( j=0; j < sizec; j++ ) {
//scanf("%d",((A+i)+j));
scanf("%d",&A[i][j]); // use array style, which should be easier to understand
}
} // add } to do multiple things
Also note that:
scanf("%d",((A+i)+j)); is wrong and it should be scanf("%d",(*(A+i)+j)); if you hate [] operator.
Casting result of malloc() family is discouraged in C.