Ascii to lower / upper
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#include <stdio.h>
#include <stdint.h>
#include <string.h>
int main(void) {
char text[8] = "Hell^23o";
size_t len = strlen(text);
uint64_t mask = 0;
for (size_t i = 0; i < 8; ++i) {
if ((text[i] >= 'a' && text[i] <= 'z') || (text[i] >= 'A' && text[i] <= 'Z'))
mask |= (size_t)0x20 << (i * 8);
}
*(uint64_t *)&text &= ~mask;
printf("Upper: %.8s\n", text);
*(uint64_t *)&text |= mask;
if (len < 8) {
text[len] = 0;
}
printf("Lower: %.8s\n", text);
return 0;
}
C
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