Thread: How to change a number to char*? Like 50 --> "50"

How to do it in the simplest method?

thank Salem!!!

I have a problem about precision multiplication. The code I wrote below.

Code:

int charToInt(char x)
{ return (int)(x-'0'); }

char intToChar(int x)
{ return (char)(x+'0'); }

void reverse(char *x, int lenX)
{
	int i;
	char t;
	for (i = 0; i < (int)(lenX/2); i++) {
		t = x[i];
		x[i] = x[lenX-i-1];
		x[lenX-i-1] = t;
	}
	for (i = 0; i < lenX; i++)
		printf("%c", x[i]);
	printf("\n");
}

char *precMult(char *a, char *b, int *lenC, int lenA, int lenB)
{
	int i, j, lenMax, lenMin;
	int *tmp;
	char *c;
	lenMax = MAX(lenA, lenB);
	lenMin = MIN(lenA, lenB);
	tmp = malloc((lenA+lenB+1) * sizeof *tmp);
	c = malloc((lenA+lenB+1) * sizeof *tmp);
	reverse(a, lenA);
	reverse(b, lenB);
	for (i = 0; i < lenMax; i++)
		tmp[i] = 0;
	for (i = 0; i < lenMin; i++) {
		for (j = 0; j < lenMax; j++) {
			tmp[i+j] += charToInt(a[j])*charToInt(b[i]);
			if (tmp[i+j] >= 10) {
				tmp[i+j+1] += (int)tmp[i+j]/10;
				tmp[i+j] %= 10;
			}
		}
	}
	*lenC = lenA+lenB-1;
	if (tmp[lenA+lenB-1] > 0)
		(*lenC)++;
	for (i = *lenC-1; i >= 0; i--)
		c[i] = intToChar(tmp[i]);
	free(tmp);
	return c;
}

How to do a action like "a = precMult(b, c, lenB, lenC, &lenA)". a, b, c are array. lenA, lenB, lenC are int.

yes, dwks. I wanna change the order of arguments.