Question

See this code:

int main() {
    char a[50];
    FILE *fp;

    fp = fopen("test1.txt", "w");

    sprintf(a,"jigar %d \n", 3);
    fprintf(fp,"jigar %d \n", 3);

    sprintf(a,"patel %d \n", 2);
    fprintf(fp,"patel %d \n", 2);
    printf("%s", a);
}

Here, using fprintf, I can write in file

jigar 3 
patel 2 

where same functionality I want where what ever I print that goes in one char buffer.

but using sprintf gives me on buffer

patel 2 

I have so many such print which I want to add in one char buffer and then I need to return it to application so how to get it in simplest and fastest way this?

Answer 1

sprintf() returns the number of characters printed.

Just use that number for the next write …

int i;
char a[50];
char *ap = a;

for (i = 5; i < 15; i++) {
    ap += sprintf(ap, "%d ", i);
}

printf("%s\n", a); /* "5 6 7 8 9 10 11 12 13 14 " */

Make sure you don’t cause any buffer overflows though.