C/C++: Floating point exception (core dumped) — SIGFPE, usually integer division by zero

Meaning

On x86 the CPU traps integer x / 0 and x % 0, and the OS reports SIGFPE as "Floating point exception". Floating-point division by zero normally produces inf or nan instead. Find the divisor that became zero: an empty input, a count that was never incremented, or a loop that starts at 0.

Common causes

• Integer division or modulo by zero (avg = sum / count with count == 0)
• INT_MIN / -1 overflow
• Empty container used to compute an average
• Divisor read from input or config that was left at 0
• Unchecked % in hashing code with table size 0

Detailed fix by platform

Code examples

#include <vector>
#include <numeric>

double average(const std::vector<int>& v) {
    if (v.empty()) return 0.0;                           // avoids dividing by zero
    return std::accumulate(v.begin(), v.end(), 0.0) / v.size();
}

int bucket(int hash, int buckets) {
    return buckets > 0 ? hash % buckets : 0;            // int % 0 would raise SIGFPE
}

How to diagnose

1. Line — Which expression divides?
2. Value — Can the divisor be zero or empty?
3. Type — Integer or floating-point?

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